furniturerepairtools
I'm trying to take apart an old bed frame. The fasteners are square head bolts, but they're tucked away with only 1/2" of clearance to access them.
I can't find square head bits shorter than an inch, so I've got no idea how it was put together in the first place.
Is there such a tool out there?
You took the wind out of my sails with that last paragraph. I was going to suggest using a nut/bolt.
As far as it causing problems when the tabletop is lowered, you can recess the bolt head. Yeah, you could make the cavity in which the bolt will stay on the underside of the tabletop, but maybe you'll drill too far or crack/scratch the tabletop if you chisel it out. It could end badly... which is why you should instead house the bolt head on the top-side of the cross member.
Brown = table top
Black = underlying cross member
The one on the left is what you were talking about. The one on the right is what you want to do.
Also, use a washer under the bolt head, etc.
I think what you need is a Palm Nailer. You can get these in air or electric powered versions. They are compact and are handy to drive nails in tight spaces.
Best Answer
I can barely make it out, but it looks like a pin-and-slot arrangement. Bump the rail with your palm away from the camera. The bracket that's retained by the screw should slide off the pin we see deeper in. If it doesn't budge, use a mallet or a hammer and block of wood.